Process Intensification by Microstructured Membrane Reactors

As described above, the principle of an extractor-type membrane reactor has been extensively demonstrated, most often with mbular membranes of 5-10 mm diameter and catalysts having a particle size of around 1 mm in small laboratory reactors where the catalyst is placed as a packed bed inside or around the membrane tube. For Pd-alloy membranes 

With the square root of ratio of the hydrogen partial pressure in permeate versus retentate gas phase, p, and the ratio of the mass transfer resistances of film versus membrane, O, 

kQ is the mass transfer coefficient describing the diffusion resistance and H represents the membrane permeability. Following [129], an expression can be derived relating the film effectiveness factor to these two dimensionless variables. High values of O indicate high mass transfer resistance of the film compared to the membrane and thus strong concentration polarization. 

no less important aspect for technical reformers is the supply of heat to drive the endothermic reaction. In conventional systems, gas-fired burners are used to heat the outside surface of the reformer mbes. For large tubes used in world-scale reformer plants, the reaction is strongly heat transfer limited, which increases the fuel consumption by the burners. And also at smaller scale, the consequences of concentration and temperature gradients for system performance can be remarkable pointing out the need for optimal reactor design. 

I Pt resistive heaters, 200 nm Pd-Ag permseiective fiim, 200 nm I Siiicon nitride, 300 nm Siiicon substrate, 0.65 mm 

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